<template>
  <div>
    <p>请选择你要购买的书籍</p>
    <ul>
      <li
        v-for="(obj,index) in arr"
        :key="index"
      >{{obj.name}}
        <button @click="addBock(index)">买书</button>
      </li>
    </ul>
    <table
      border="1"
      width="500"
      cellspacing="0"
    >
      <tr>
        <th>序号</th>
        <th>书名</th>
        <th>单价</th>
        <th>数量</th>
        <th>合计</th>
      </tr>
      <tr
        v-for="(obj,index) in arr"
        :key="obj.id"
      >
        <th>{{index+1}}</th>
        <th>{{obj.name}}</th>
        <th>{{obj.price}}</th>
        <th>{{obj.count}}</th>
        <th>{{obj.price * obj.count}}</th>
      </tr>
    </table>
    <p>总价格为:{{allPrice}}</p>
  </div>
</template>

<script>
export default {
  data () {
    return {
      arr: [
        {
          name: "水浒传",
          price: 107,
          count: 0,
        },
        {
          name: "西游记",
          price: 192,
          count: 0,
        },
        {
          name: "三国演义",
          price: 219,
          count: 0,
        },
        {
          name: "红楼梦",
          price: 178,
          count: 0,
        },
      ],
    };
  },
  methods: {
    addBock (ind) {
      this.arr[ind].count++
    }
  },
  computed: {
    allPrice () {
      return this.arr.reduce((sum, obj) => sum += obj.price * obj.count, 0)
    }
  }
};
</script>